Light-tran-smitter



(No Model.)

G. K. CUMMINGS.

LIGHT TRANSMITTER.

Patented Nov. 2,1897.

as? a v Ag ATTORNEY WITNESSES:

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GEORGE K. CUMMINGS, OF CHICAGO, ILLINOIS.

LIGHT-TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 593,045, dated November 2, 1897. Application filed May 28, 1897. Serial No. 638,502. (No model.)

To all whom it may concern:

Be it known that I, GEORGE K. CUMMINGS, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Light-Transmitters, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to panes of translucent or transparentmaterial; and its object is to provide a pane of such construction as will be adapted to light up the dark interior rooms or spaces in a building in a most efficient manner and will cause the light to be evenly, uniformly, and thoroughly diffused throughout such room or space.

My invention consists in a new article of manufacture comprising a pane or light of suitable transparent or translucent material made in a single piece and provided on one side with a series of parallel triangular projections and on the other side with a series of parallel convex projections placed edge to edge, so that the end of one convex surface meets the end of the adjoining convex surface without leaving any intervening spaces, the curve of each convex surface being uniform-that is, struck from a single center or axis--and the convex projections being parallel with the triangular projections, whereby one side of the pane is made up of flat surfaces placed at an angle to the median line of the pane and the other side is made up Wholly of convex surfaces of a uniform curvature.

My invention is fully shown in the accompanying drawings, in which- Figure 1 is a perspective view of my improved pane, showing one side thereof. Fig. 2 is a similar view showing the other side thereof. Fig. 3 is a cross-section of a part of a plate with lines indicating the direction of rays of light falling on the convex projections as the incident side, and Fig. 4 is a similar cross-sectional View with lines indicating rays of light falling on the prismatic projections as the incident side.

Referring to the drawings, A is a pane or vided on one side with a series of triangular prismatic ribs or projections 19, which are made integral with the plate and extend from side to side thereof. The form of these projections, so far as relates to the angles which the sides thereof make with each other and with the median line of the plate, maybe varied according to circumstances. I prefer to use'this face of the plate as the outside orincident side, and I prefer to shape the triangular projection so that one of its sides will be nearly at a right angle to the general or prevailing direction of the rays of light. The pane is provided on its other side with a series of parallel convex ribs or projections a, which are in like manner made integral with the plate and extend from side to side thereof. The convex surfaces are made with a uniform curvaturethat is, each convex surface is struck from a single or common center or axisso that a cross-section of any one of these projections at any point will show the outer surface in the form of an arc of a circle.

The convex projections are placed edge to edge, so that the end or edge of one convex surface meets the end or edge of the adjoining surface, and so on; or, to describe this feature in other words, the convex surface of each projection is bounded by an arc of a circle, the arc of each projection joining or intersecting the arcs of the adjacent projections. As a result of this, there are no inter vening spaces between the convex projections, and these projections cover the entire face of the plate. The convex projections are parallel to the triangular projections on the other side of the plate.

The'operation of my improved pane or plate is as follows: In any situation Where such a light-transmitter is to be used it is generally true that a large part of the rays of light come from one general direction. I arrange one side of my triangular projection so that it will be nearly perpendicular to this general direction. This will cause the largest possible amount of the light to enter the pane and will reduce to a minimum the loss light resulting from reflection from the incident surface. The rays of light that enter the pane will be refracted therein unless they pass straight through by reason of having fallen on the incident surface at right angles thereto,

and will emerge from the convex surfaces. By reason of the shape of the convex projections the rays of light that are parallel when passing through the pane, when they emerge therefrom, will be focalized along a line some distance beyond the convex surface and after passing the focal line will diverge, so as to spread and diffuse the light. In most cases, in addition to the rays of light coming from the main general direction, there is a large number of rays reflected from adjoining objects and falling on the incident surface from almost every direction. These rays Will emerge from the convex projections in every direction within the limits of the convex surface of the said projections, and the light emerging from each convex projection will therefore spread out or radiate beyond its focal lines into a fan-like form or space, and the fan-shaped area of light from one convex projection willoverlap the fanshaped area of light from the adjoining projection. In this way the light is not only thoroughly spread and diffused, but it is made even and of maximum intensity. Very little, if any,

'lightis lost by internal reflection.

As the projections and the intervening septum of the plate are made integral, it follows that rays of light falling on the incident surface opposite one of the convex projections, but at such an angle that they cannot emerge from that convex projection, will, nevertheless, emerge from the adjoining eonvex projection, and in this way be saved and utilized.

In some cases where the outside light is rather diffused the convex projections may be used as the incident side; but I have secured the best results in the manner above described. In Fig. 3 I have illustrated by means of a few lines representing rays of light the direction which those rays would take if the convex surface were incident.

This convex surface may be conceived of as made up of an infinite number of planes, and the rays of light coming from many different directions strike these planes at angles of incidence that minimize the reflection, so that the greatest possible amount of light onters the plate. These rays pass through the plate in their several and numerous directions andare refracted in a diffused manner and in divergent directions from the plane prism-surfaces.

\Vhat I claim as'new, and desire to secure by Letters Patent, is

1. As a new article of manufacture, a pane or light made of a single piece of translucent material and provided on one side with a series of parallel triangular prismatic ribs or projections and on the other side with a series of parallel convex projections, the convex surface of each projection being bounded by an arc of a circle, the are of each projection joining or intersecting the arcs of the adjacent projections, and the convex projections being parallel with the triangular projections, substantially as set forth.

2. Asa new article of manufacture, apane or light made of a single piece of translucent material and provided on one side with a series of parallel triangular prismatic ribs or projections, and on the other side with a series of parallel convex projections, the convex surface of each projection being bounded by an arc of a circle, the are of each projection joining or intersecting the arcs of the adjacent projections, and the convex projections being parallel with the triangular projections and being placed opposite thereto, substantially as set forth.

GEORGE K. CUMMIN iii.

\Vituesses:

S. STOUT, W. T. OAsonAiN. 

